Dokładność nowego hybrydowego uogólnionego modelu falkowo-sieciowego z długą pamięcią do krótkoterminowego prognozowania cen energii elektrycznej [Predictive accuracy of a new hybrid generalized long memory wavelet-neural networks model for short term electricity price forecasting] Souhir Ben Amor (High Institute of Commercial Studies of Sousse, IHEC, Tunisia) Accurate electricity price forecasting is the main management goal for market participants since it represents the fundamental basis to maximize the profits for market players. However, electricity is a non-storable commodity and the electricity prices are affected by some social and natural factors that make the price forecasting a challenging task. This study investigates the predictive performance of a new hybrid model based on Generalized long memory autoregressive model (k-factor GARMA), the Gegenbauer Generalized Autoregressive Conditional Heteroscedasticity(G-GARCH) process, Wavelet decomposition, and Local Linear Wavelet Neural Network (LLWNN) optimized using two different learning algorithms; the Back propagation algorithm (BP) and the Particle Swarm optimization algorithm (PSO). The performance of the proposed model is evaluated using data from Nord Pool Electricity markets. Moreover, it is compared with some other parametric and non-parametric models in order to prove its robustness. The empirical results prove that the proposed method performs better than other competing techniques. (*) Based on joint work with Heni Boubaker and Lotfi Belkacem (High Institute of Commercial Studies of Sousse, IHEC).